Percussion apparatus



Feb. 13, 1923. 1,444,815

I J. w. VAN METER PERCUSSION APPARATUS Filed Jan. 14, 1920' 2sheets-sheet 1 INVENTOR James W Vanfileiez' Feb. 13, 16923.

J. W. VAN METER PERCUSSION APPARATUS Riled Jan 14, 1920 2 sheets-sheet 2INVENTOR- hmes WT VmMeafer Amonnm! Patented Feb. 13, 1923.

JAMES W. VAN METER, OF SAN FRANCISCO, CALIFORNIA.

PERCUSSION APPARATUS.

Application filed January 14, 1920. Serial No. 351,318.

of trip hammers and other well known percussion devices. The presentdevice may be used for a variety of purposes by changing t ie form ofthe piston and anvil. It is particularly advantageous for stamping ores,metal, and the like.

The. present form of the device is that of a cylinder and piston whereinan explosive charge is made use of to drive the piston upward against ananvil. Two chambers are made use of, one receiving the explosive chargeto drive the piston and the other serving as a counterbalancing andcushion ing chamber for the heavy piston. I employ air under pressure toobtain the necessary compression of the charge of explosive mixture inthe working chamber, and after the charge is exploded, the force of theblow is augmented by admitting compressed air to the second chamber,such air being also used to cushion the weight of the piston in itsdownward stroke. While the present device is shown as being operated byan explosive mixture, I do not limit myself to that form of operation,and desire to point out that steam, compressed air, or any othersuitable agent may be used to drive the piston.

In the accompanying drawings Fig. 1 shows a vertical central sectionalview of a device embodying my invention.

Fig. 2 shows a similar view partly in elevation.

Fig. 3 shows a side elevation of the device partly in section.

The device as here shown comprises an upright frame 10 resting on a base11. The frame 10 is provided at its upper end with a cylinder 12 havinga large and small bore within for the purpose of receiving a doublepiston 13 and 14. The upper bore is used as a cushioning andcounterbalancing chamber and the lower bore is used as an explosivechamber. The upper extremity of the frame 10 is fitted with two uprightmembers 15 on which rests a crosshead or anvil 16 secured to theuprights by nuts 17. This anvil or: crosshead receives the blow fromthehead of the piston 13.

The frame 10 is held in position on the base 11 by means of a system ofsupporting rods 18 which form a tripod. A projecting rim 19 on thebottom of the frame 10 carries a rubber buffer 20 resting against a circular ring 21, which latter is secured to thebase 11 by means of bolts22. The legs of the tripod have their upper ends fitting loosely intosockets in the frame 10 and at their lower ends are screwed into nuts23, which latter rest on rubber cushions 24 seated in cups 25 on thebase 11. The purpose of this construction is to lift the frame 10 andhold it closely against the rubber buffer 20. The weight of the framenormally rests on the legs 18 and these in turnrest on the base throughthe cushions 24. The shock caused. by the upward blow of the piston willbe taken up by the buffer 20 and the jar, if any, resulting from thedescending piston will be received by the cushions 24.

The pistons 13 and 14 areprovide'd with rings. 26 and 27 whereby to forma tight sliding fit with the walls of the surrounding cylinders. Thebottom of the upper cylinder is fitted with a rubber disk 28 to formacushion for the descending piston. An air-passage 29 is formed in thewall of the upper cylinder and is fitted with a checkvalve 30 openingoutwardly, said valve being maintained in closed position by means of anadjustable spring. A pipe 31 forms a I communication between theair-passage 29 and an air reservoir 32. A circular recess 33extendsentirely around the wall of the upper cylinder and a series ofports 34 opening into the interior ofthe cylinder. This annularpassageway is in communication also with the air reservoir 32 throughthe pipe 31. p

The lower chamber is provided with a piston valve 35 actuated by ahandle 36, said valve serving to control the admission of compressed airto the lower cylinder. Air under pressure is supplied from a tank 37through a valved pipe 38 and ports 39. Liquid fuel is admitted with thecompressed air by means of a small pump 40 in the bottom of the frame10, said pump being actuated by an extension 41 on the end of the handle36. The liquid fuel is suppliedto the pump through a pipe 42. Theexplosive mixture, after entering the lower chamber, is ignited by meansof a spark plug 43, the circuit through which is closed by means of avertical rod 44L in the lower end of the upper cylinder, said rod beingnormally pressed upwardly by a spring and being positioned to movedownwardly when the upper piston reaches the bottom of its cylinder.With the upper piston at the bottom of its cylinder, the rod 441- willbe moved down-' wardly to break the circuit, but when the piston ismoved upwardly some distance, the rod 44- will rise under pressure orthe spring to close the circuit, thereby serving as a timer for;igniting the charge in the lower chamber. A. check-valve 45 is fitted inthe side of the upper cylinder and opens inwardly, serving to admit airto the upper chamber when an excess of vacuum is. present therein. I

In the operation of the device herein shown and described, a chargeofliquid fuel is forced by the pump 40 into the chamber of the pistonvalve 35. and is inturn picked up by means of the compressed air andcarried into the lower chamber. The lower piston willstart to rise whensuiiicient pressure has been accumulated within the combustion chamberto counterbalance the weight of the piston. However, the piston isrestrained against upward movement by reason of a tendency to form avacuum in the upper cylinder. When the upper piston reaches the linedesignated All), the timer a l will close the circuit to ignite theexplosive charge whereupon the upper piston will uncover the ports 34:admitting compressed air from the reservoir 32 which will augment theforce of the explosion and drive the piston upwardly against the anvil.

The blow having been struck, the handle 36 isli'fted to uncover the portin the lower end of the lower chamber to the atmosphere and allow theburned gases to escape through the open end 35 or the sleeve of thepiston valve 35. It should be understood that the pressure of air in theupper chamber is maintained at a point slightly below what is requiredto support the heavy piston and therefore-the piston will slowly descendonce the forceof the explosive mixture has been dispelled. The air inthe upper chamber is forced back into the reservoir 32, first throughthe ports. 34- until they have been covered and thereafter through thecheck valve .30. allowing the piston to gradually and slowly settle tothe bottom of the cylinder where it will rest upon the rubber disk 28.The reservoir 32 is shown as being supplied with or through a valvedpipe 32 from the reservoir 37, and it has safety valve 32 to maintainthe pressure at the desired point. In the initial stage of operation ofthe piston, should the vacumin the upper chamber become too great toallow the piston to rise to a point where the timer 44: is set'ofi thenthe check valve 45 will open to admit air from the outside.

Among the many advantages of my apparatus is that I accumulate thenecessary pressure in the working cylinder by utilizing the weight ofthe piston andv a slight vacuum or suction in the upper chamber whichtends to restrain thev upward movement of the piston until the ports 34are uncovered. Also, after the explosive charge has been hired, and thepiston 13 uncovers the ports 34, there is an inrush of air underpressure from the reservoir 32 which will assist the upward movement ofthe piston, such air remaining to cushion the descent of the piston. Thespeed of descent of the piston can be accurately controlled, and uponreaching its lowermost limit, it is cushioned by the rubber mat 28. Alsoof advantage in the construction of this apparatus is the rubber ringQOfor cushioning the frame when the blow struck and the rubber blocks 24-take up any shocks incident to the return of the piston.

Various changes in the constructionand arrangement of the several partsmay be employed without departing from the spirit of my invention asdisclosed in the appended claims.

The presence oi the rubber mat 20 in the bottom of the upper chamberinsures a complete expulsion of all air pressure from the chamber whenthe piston reaches the bottom of the cylinder: Thereiore, on the initialup stroke 01" the piston 13, there is certain to be the necessary vacuumor suction to restrain the piston.

I roving thus described my invention, what i claini and desire to secureby Letters Patent is:

1. A percussion apparatus comprising a cylinder, and piston, means foradmitting'an explosive mixture under pressure at one end of thecylinder, means for retarding the movement of said piston while theexplosive mixture is being admitted, and means for exploding saidmixture when the piston has moved a predetermined degree under theinfluence of the explosive mixture under pressure.-

A percussion apparatus comprising a superposed anvil, an upwardly movingpi sploding said mixture when the piston has moved a predetermineddegree under the influence of the explosive mixture under pressure, andmeans for admitting air under pressure after said explosion, said airbeing adapted to aid in advancing the piston.

4. A percussion apparatus comprising a superposed anvil, an upwardlymoving piston to co-operate therewith, a working chamber for explosivefluid to drive the said piston upwardly against the anvil and a secondchamber for expansive fluid to assist in lifting the piston on theupward stroke and effective to cushion the return stroke of said piston.

5. A percussion apparatus comprising a superposed anvil, an upwardlymoving piston to co-operate therewith, a working chamber for explosivefluid to drive the said piston upwardly against the anvil and a secondchamber for expansive fluid to assist in lifting the piston on theupward stroke and effective to cushion the return stroke of said piston,said second chamber being below atmospheric pressure until the explosivecharge is ignited, whereby to restrain upward movement of the piston andpermit compression of the explosive charge in the working chamber.

6. A percussion apparatus comprising a double piston and cylinderforming two chambers, one for explosive mixture and the other forexpansive fluid co-operating to drive the piston upwardly forcefully andto cushion the descent of the piston.

7. A percussion apparatus comprising a double piston and cylinderforming two chambers, one for explosive mixture and the other forexpansive fluid co-operating to drive the piston upwardly forcefully andto cushion the descent of the piston, said second chamber being normallybelow atmospheric pressure until the explosive charge is ignited, andthereafter open to admit compressed air to assist in lifting the piston.

8. A percussion apparatus comprising a double piston and cylinderforming two chambers, one for explosive mixture and the other forexpansive fluid co-operating to drive the piston upwardly forcefully andto cushion the descent of the piston, said second chamber being normallybelow atmospheric pressure until the explosive charge is ignited andthereafter open to admit compressed air to assist in lifting the piston,the compressed air in said second chamber being slightly less thanrequired to support the cally therein, a superposed anvil against whichone end of the piston is adapted to strike, means for admittingexplosive mixture in said cylinder adjacent the other end of the pistonwhereby with the explosion thereof the piston willbe impelled againstthe anvil, and means interposed between the base and cylinder adapted tocushion the force of the upward blow delivered by the piston to theanvil, and to likewise cushion the shock of the returning piston.

11. A percussion apparatus comprising a cylinder, a piston therein, acombined pump and valve mechanism for admitting an explosive mixtureunder pressure at one end of the cylinder, means for retarding themovement of said piston while the explosive mixture is being admitted,and means for exploding said mixture when the piston has moved apredetermined degree under the influence of the explosive mixture underpressure.

12. A percussion apparatus comprising a double piston, separate chamberstherefor, one receiving an explosive charge to drive the piston upwardlyand the other acting initially by vacuum to restrain the upward movementof the piston, and afterwards receiving an expansive fluid tocounterbalance and cushion the piston, and acompressible mat in thebottom. of the last named chamber to insure a seat for the piston andobtain a complete expulsion of expansive fluid from the piston chamberwhen said piston completes its downward stroke.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

JAMES W. VAN METER.

Witnesses 7. W. HEALEY, M. E. EWING.

